Organozirconium compound, organic solution comprising same, and zirconium-containing thin film therefrom

ABSTRACT

An organozirconium compound comprises zirconium complexed with a β-diketone compound and an alkoxy group having a branched alkyl group, and which has formula (1):                    
     wherein R is a branched alkyl group having 4 or 5 carbons; and L 1 , L 2 , and L 3 , the same or different from each other, are each a β-diketone compound.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an organozirconium compound and anorganic solution comprising the compound for the preparation of azirconium-containing thin film by the Metal Organic Chemical VaporDeposition method (referred to as MOCVD hereinafter), and also relatesto a zirconium containing thin film formed using the organozirconiumcompound and an organic solution of the compound. More particularly, thepresent invention relates to an organozirconium compound and an organicsolution comprising the compound for preparing a Pb(Zr,Ti)O₃ (referredto as PZT hereinafter) thin film by the MOCVD method in the preparationof ferro-electric memories.

2. Description of the Background

An organozirconium compound which is known to be useful in the MOCVDmethod (referred to as MOCVD-organozirconium compound hereinafter) iszirconium tetra(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to asZr(thd)₄ hereinafter). Another compound known to be useful in the MOCVDmethod is the organolead compound, leadbis(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to as Pb(thd)₂hereinafter). Still another useful compound in the MOCVD method isdiisopropoxy titanium bis(2,2,6,6-tetramethyl-3,5-heptadionate)(referred to as Ti(iPro)₂(thd)₂ hereinafter).

However, it is reported that Zr(thd)₄, as an MOCVD-organozirconiumcompound, exhibits the problem that the film deposition temperature ofZr(thd)₄ deviates from the temperatures of the other two compounds whenforming a PZT thin film, since Zr(thd)₄ has a higher decompositiontemperature in comparison to that of Pb(thd)₂, which is anMOCVD-organolead compound and that of Ti(iPro)₂(thd)₂, which is anMOCVD-organotitanium compound (Anthony C. Jones et al., Journal of theEuropean Ceramic Society, 19 (1999) 1431-1434). To solve this problem,it has been proposed to use tetratertiarybutoxy zirconium (referred toas Zr(tBuO)₄ hereinafter) in this role, since it has a low decompositiontemperature. However, this compound is extremely reactive with the air,and therefore, has the different problem of being extremely difficult tohandle.

Compared to this, published PCT application WO98/51837 (PCT applicationnumber: PCT/GB98/01365), describes new organozirconium compounds whichare useful in the MOCVD method, which are diisopropoxy zirconiumbis(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to asZr(iPrO)₂(thd)₂ hereinafter), ditertiarybutoxy zirconiumbis(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to asZr(tBuO)₂(thd)₂ hereinafter), Zr₂(iPrO)₆(thd)₂, and the like. Thesecompounds are superior to the above-described conventional compounds inthat they can be used for film deposition over a wide temperature range.

In the meantime, Okuhara et al., have proposed a new organozirconiumcompound for the MOCVD method which is isopropoxy zirconiumtris(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to asZr(iPrO)₁(thd)₃ hereinafter). This compound exhibits a high vaporpressure as a monomer and is readily soluble in a solvent (47th AppliedPhysics-related Joint Lectures, Preliminary Report, (March, 2000),p.540).

However, organozirconium compounds such as Zr(iPrO)₂(thd)₂,Zr(tBuO)₂,(thd)₂, and Zr₂(iPrO)₆(thd)₂, which are described in publishedPCT application WO98/51837, exhibit the problem of tending to react withthe above-described Pb(thd)₂ and similar compounds, leaving largeamounts of unvaporized residues at vaporization, when the compounds aremixed with them in order to form a PZT thin film by the MOCVD method.

Regarding the organozirconium compounds represented by Zr(iPrO)₁(thd)₃described by Okuhara et al. above, they leave large amounts of residueupon vaporization. Moreover, if the compounds are mixed with othercompounds such as Pb(thd)₂, they also tend to react with each other,further increasing residues upon vaporization. This poses anotherproblem.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide anorganozirconium compound having a decomposition temperature which islower in comparison to those of the above-described conventional MOCVDorganozirconium compounds and which is near to the decompositiontemperatures of MOCVD organolead compounds and organotitanium compounds.

Another object of the present invention is to provide an organozirconiumcompound which, upon vaporization, only leaves a small amount ofresidue.

Still another object of the present invention is to provide anorganozirconium compound which only reacts with difficulty with eitherone or both of an MOCVD organolead compound and an MOCVD organotitaniumcompound and, when mixed with these compounds and upon vaporization ofthe mixture, leaves only a small amount of residue.

Yet another object of the present invention is to provide an organicsolution which enables more accurate control of the composition of a PZTthin film.

Still another object of the present invention is to provide azirconium-containing thin which is uniform and easily controllable.

Briefly, these objects and other objects of the present invention ashereinafter will become more readily apparent can be attained by anorganozirconium compound which comprises zirconium combined withβ-diketone compounds and an alkoxy group having a branched alkyl group,and which is represented by formula (1):

wherein R is a branched alkyl group having 4 or 5 carbons; and L₁, L₂,and L₃, are the same or different from each other, and each are aβ-diketone compound.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Since the central metal in the organozirconium compound of the firstaspect of the present invention has an alkoxy group having a bulkybranched alkyl group and β-diketone compound ligands coordinated to thezirconium atom at a metal to ligand ratio of 1:3, the compound itselfleaves only small amounts of residues upon vaporization of the complex.For the same reason, the complex has a decomposition temperature nearthose of organolead compounds and organotitanium compounds, and whenmixed with them, it is hard to react the zirconium complex with theorganolead compounds and organotitanium compounds, leaving only smallamounts of residues upon vaporization.

The second aspect of the present invention is an organic solutioncomprising the organozirconium compound of the first aspect of thepresent invention dissolved in an organic solvent together with eitherone or both of Pb(thd)₂ and Ti(OR′)₂(thd)₂. The second aspect of thepresent invention also encompasses an organic solution comprising anorganozirconium compound of the first aspect of the present inventiondissolved in an organic solvent together with either one or both ofPb(tod)₂ and Ti(OR′)₂(tod)₂. Here, thd is a2,2,6,6-tetramethyl-3,5-heptadionate group, tod is a2,2,6,6-tetramethyl-3,5-octadionate group, and R′ is a straight-chain orbranched alkyl group having 3 to 5 carbons.

During film deposition, the organic solution comprising anorganozirconium compound of the first aspect of the present invention,which is mixed and dissolved in an organic solvent together withPb(thd)₂, Ti(OR′)₂(thd)₂, Pb(tod)₂, or Ti(OR′)₂(tod)₂, does not cause anincrease of residues upon vaporization as a result of mixing and,therefore, can be stably supplied to an MOCVD apparatus. Furthermore,since vaporization temperatures and decomposition temperatures of theorganozirconium compound, organolead compound, and organotitaniumcompound are near each other, it is possible to improve control of thecomposition of a PZT thin film.

The second aspect of the present invention is a raw material solution,wherein R′ is the same as the branched alkyl group (R) represented informula (1) shown in the first aspect of the present invention.

By selecting the same group for R and R′, the problem of exchange ofalkoxy groups is solved, and changes in characteristics of the compoundsare limited.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the invention and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings, wherein:

FIG. 1 is a graph of the mass spectrum of the purified powder product(Zr(tBuO)₁(thd)₃) of Example 1;

FIG. 2 is a graph of the mass spectrum of the purified powder product(Zr(tAmylO)₁(thd)₃) of Example 2; and

FIG. 3 is a graph of the results of thermogravimetric analysis of theorganozirconium compounds described in Examples 1 to 3 and ComparativeExample 1, respectively.

The organozirconium compound of the present invention is a compoundhaving formula (1). R of formula (1) is a branched alkyl group having 4or 5 carbons, and L₁, L₂, and L₃, the same or different from each other,are each a ligand of a β-diketone compound. When the number of carbonatoms in R is three or less, a problem is encountered of reactionsoccurring with other organolead compounds or organotitanium compoundswhen the organozirconium compound is mixed with these compounds. Whenthe number is six or more, a problem which is encountered is that thealkoxy group decomposes leaving carbon in the film which is formed.Furthermore, if a straight-chain alkyl group is used as the alkyl group,reactions between the compounds tend to occur easily and control of thereactions when the organozirconium compound is mixed with otherorganolead compounds or organotitanium compounds is more difficult,since the alkyl group is less bulky. Therefore, a branched alkyl groupis selected as the alkyl group in the present invention.

A tertiary alkoxy group is preferred as the alkoxy group (OR) having abranched alkyl group in the formula (1). Because the alkoxy group isbulky, reactions between the compounds can be limited. The tertiarybutyl group and the tertiary amyl group are preferred as the branchedalkyl group (R), since they are bulky in addition to their relativelysmall number of carbons and, therefore, leave only a small amount ofcarbon residues in the film at film deposition.

Furthermore, the β-diketone compound (L₁, L₂, or L₃) in formula (1) hasthe structure shown in formula (2).

Here, R₁ and R₂ are each selected from the group consisting of methyl,ethyl, normal propyl, isopropyl, normal butyl, isobutyl, tertiary butyl,tertiary pentyl, neopentyl, trifluoromethyl and pentafluoroethyl. Such agroup is selected based on the fact that when the organozirconiumcompound is mixed with other organolead compounds or organotitaniumcompounds, reactions between the compounds are limited, carbon residuesin a film which is formed caused by decomposition are reduced, and thecoordinated compounds have a certain level of vapor pressure.

It is possible to dissolve only an organozirconium compound of thepresent invention in an organic solvent to form an organic solution, andthen to form a zirconium-containing thin film according to the presentinvention, using the organic solution as a raw material solution.Furthermore, it is possible to form a PZT thin film using an organicsolution of the present invention. To form this PZT thin film, anorganic solution is prepared by dissolving an organozirconium compoundof the present invention in an organic solvent together with Pb(thd)₂and Ti (OR′)₂(thd)₂, or Pb (tod)₂, and Ti(OR′)₂(tod)₂. Suitable organicsolvents include tetrahydrofuran, methyltetrahydrofuran, butyl acetate,octane, and the like.

The above-described zirconium-containing thin film or PZT thin film isuniform. Further, by using the organozirconium compound of the presentinvention, control of the method of preparing the film product therefromis easy.

Having now generally described this invention, a further understandingcan be obtained by reference to certain specific examples which areprovided herein for purposes of illustration only and are not intendedto be limiting unless otherwise specified.

Examples of the present invention are described together withComparative Examples. Examples 1 to 3 show how to synthesizeorganozirconium compounds of the present invention, while ComparativeExamples 1 to 6 show how to synthesize organozirconium compounds of theprior art.

EXAMPLE 1

Zr(tBuO)₄ in an amount of 5.0 g (0.013 mol) was dissolved in 500 cc oftoluene to form a solution. 2,2,6,6-Tetramethyl-3,5-heptadione (referredto as Hthd hereinafter) in an amount of 7.2 g (0.039 mol) was titratedinto this solution, followed by reaction with heating and refluxing at110° C. for 4 hours. Toluene in this reaction solution was removed undera reduced pressure to form a crude product. This crude product wasrecrystallized in hexane to provide a purified powder product. Thispurified product was subjected to analysis with a mass analyzer. Themass spectrum is shown in FIG. 1. From the mass spectrum, the purifiedproduct was identified as tertiarybutoxy zirconiumtris(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to asZr(tBuO)₁(thd)₃ hereinafter).

EXAMPLE 2

Tetra(2-methyl-2-butoxy) zirconium (or tetratertiaryamyloxy zirconium,referred to as Zr(tAmylO)₄ hereinafter) in an amount of 5.7 g (0.013mol) was dissolved in 500 cc of toluene to form a solution. Hthd in anamount of 7.2 g (0.039 mol) was titrated into this solution, followed byreaction with heating and refluxing in the same way described inExample 1. Toluene in this reaction solution was removed under reducedpressure to form a crude product. This crude product was recrystallizedin hexane to provide a purified powder product. The mass spectrum ofthis purified product is shown in FIG. 2. From the mass spectrum, thepurified product was identified as tertiaryamyloxy zirconiumtris(2,2,6,6-tetramethyl-3,5-heptadionate) (referred to as Zr(tAmylO)₁(thd)₃ hereinafter).

EXAMPLE 3

Zr(tHuO)₄ in an amount of 5.0 g (0.013 mol) was dissolved in 500 cc oftoluene to form a solution. 2,2,6,6-Tetramethyl-3,5-octadione (referredto as Htod hereinafter) in an amount of 7.7 g (0.039 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct. From the mass spectrum of this purified product (not shown),the purified product was identified as tertiarybutoxy zirconiumtris(2,2,6,6-tetramethyl-3,5-octadionate) (referred to asZr(tBuO)₁(tod)₃ hereinafter).

COMPARATIVE EXAMPLE 1

Zr(thd)₄ was synthesized by the following method. That is, Zr(tBuO)₄ inan amount of 5.0 g (0.013 mol) was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 9.5 g (0.052 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EXAMPLE 2

Zr(tBuO)₂(thd)₂ was synthesized by the following method. Zr(tBuO)₄, inan amount of 5.0 g (0.013 mol), was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 4.8 g (0.026 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EXAMPLE 3

Zr(tAmylO)₂(thd)₂ was synthesized by the following method. Zr(tAmylO)₄,in an amount of 5.6 g (0.013 mol), was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 4.8 g (0.026 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EXAMPLE 4

Zr₂(iPrO)₆(thd)₂ was synthesized by the following method. Zr(iPrO)₄, inan amount of 4.3 g (0.013 mol), was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 2.4 g (0.013 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EXAMPLE 5

Zr(iPrO)₁(thd)₃ was synthesized by the following method. Zr (iPrO)₄, inan amount of 4.3 g (0.013 mol), was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 7.2 g (0.039 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EXAMPLE 6

Zr(nBuO)₁(thd)₃ was synthesized by the following method. Zr(nBuO)₄, inan amount of 5.0 g (0.013 mol), was dissolved in 500 cc of toluene toform a solution. Hthd in an amount of 7.2 g (0.039 mol) was titratedinto this solution, followed by reaction with heating and refluxing inthe same way described in Example 1. Toluene in this reaction solutionwas removed under a reduced pressure to form a crude product. This crudeproduct was recrystallized in hexane to provide a purified powderproduct.

COMPARATIVE EVALUATION (a) Thermogravimetric Analysis

Results of thermogravimetric analysis (TG) of the purified powderproducts (organozirconium compounds) described in Examples 1, 2, and 3,as well as in comparative Example 1, are shown in FIG. 3, respectively.As is evident from FIG. 3, all of Examples 1 to 3 as indicated withsolid lines show lower vaporization temperatures in comparison withComparative Example 7, indicated with a dotted line. Specifically, theorganozirconium compound described in Example 1 has an excellentvaporization temperature.

(b) Thermal Decomposition Temperature

The thermal decomposition temperatures of the purified powder products(organozirconium compounds) described in Examples 1, 2, and 3, as wellas in Comparative Example 1 were investigated, respectively.Furthermore, the thermal decomposition temperatures of Pb(thd)₂ as anorganolead compound and Ti(iPrO)₂(thd)₂ as an organotitanium compoundwere also investigated, respectively. The results are shown in Table 1.As is evident from Table 1, it is understood that the decompositiontemperatures of the organozirconium compounds described in Examples 1 to3 are nearer to those of Pb(thd)₂ and Ti(iPrO)₂(thd)₂ as anorganotitanium compound in comparison with the organozirconium compounddescribed in Comparative Example 1.

TABLE 1 Thermal composition Organometallic compound temperature (° C.)Example 1 Zr(tBuO)₁(thd)₃ 340 Example 2 Zr(tAmylO)₁(thd)₃ 360 Example 3Zr(tBuO)₁(thd)₃ 330 Comparative Zr(thd)₄ 410 Example 1 — Pb(thd)₂ 325 —Ti(iPrO)₃(thd)₃ 280

(c) Residues at Vaporization before and after Mixing with an OrganoleadCompound

The residues at vaporization of the purified powder products(organozirconium compounds) described in Examples 1 to 3, as well as inComparative Examples 2 to 5, were investigated in a single state,respectively. The residues obtained upon vaporization of mixtures ofpurified powder products with an organolead compound were alsoinvestigated, respectively.

The residues remaining after vaporization of the organozirconiumcompounds described in Examples 1 to 3, as well as in ComparativeExamples 2 to 5, before mixing with an organolead compound wereinvestigated in a single state, respectively, by performingthermogravimetric analysis (TG) by heating them up to 500° C. in anargon atmosphere.

The residues remaining after vaporization of mixtures of organozirconiumcompounds with an organolead compound were investigated by the followingmethod. First, each of the organozirconium compounds described inExamples 1 to 3, as well as in Comparative Examples 2 to 5, was mixedwith Pb(thd)₂ in are argon atmosphere. Each mixture was then dissolvedin tetrahydrofuran as an organic solvent, and each solution was dividedin half. One half of a solution was stored in an argon atmosphere underlight shielding conditions for one month. The other half was stored inthe same atmosphere for three months, and the solvents were removedunder reduced pressure upon the termination of the term of storage.After that,.thermogravimetric analysis (TG) was performed by heating thestored solutions up to 500° C. in an argon atmosphere to check theamount of residue which had formed in each solution. The results areshown in Table 2.

TABLE 2 Residues at vaporization (wt. %) Storing time after mixingBefore One Three Organo Zr compound mixing month months Example 1Zr(tBuO)₁(thd)₃ 0 0.9 0.9 Example 2 Zr(tAmylO)₁(thd)₃ 2.1 3.3 3.2Example 3 Zr(tBuO)₁(tod)₃ 2.6 4.0 3.8 Comparative Zr(tBuO)₂(thd)₂ 7.513.4 16.2 Example 2 Comparative Zr(tAmylO)₂(thd)₂ 7.2 9.8 11.6 Example 3Comparative Zr₂(iPrO)₆(thd)₂ 6.8 11.8 14.5 Example 4 ComparativeZr(iPrO)₁(thd)₃ 9.5 10.1 11.5 Example 5

As is evident from the data in Table 2, before mixing each of theorganozirconium compounds shown with Pb(thd)z, while the organozirconiumcompounds described in Comparative Examples 2 to 5 produced 6.8 to 9.5%by weight of residues at vaporization, the organozirconium compoundsdescribed in Examples 1 to 3 produced only 0 to 2.6% by weight ofresidues at vaporization. Furthermore, subsequent to one-month storageafter mixture of a given organozirconium compound with Pb(thd)₂, whilethe organozirconium compounds described in Comparative Examples 2 to 5produced 9.8 to 13.4% by weight of residues at vaporization, theorganozirconium compounds described in Examples 1 to 3 produced only 0.9to 4.0% by weight of residues upon vaporization. After storage for threemonths, while the organozirconium compounds described in ComparativeExamples 2 to 5 produced 11.5 to 16.2% by weight of residues uponvaporization, the organozirconium compounds described in Examples 1 to 3produced only 0.9 to 3.8% by weight of residues upon vaporization. Inparticular, the organozirconium compound described in Example 1 wasexcellent with regard to this matter.

(d) Vaporization Test after Mixing with other Organometallic Compounds

The purified powder products (organozirconium compounds) described inExamples 1 to 3, as well as in Comparative Examples 5 and 6, were mixedwith the organolead compound, or mixed with the organolead compound andthe organotitanium compounds as shown in Table 3, and then dissolved inthe organic solvents shown in Table 3. The solutions obtained werevaporized respectively under the conditions indicated in Table 4 using avaporizer commercially available as a vaporizer for an MOCVD apparatus.The results are shown in Table 3. Here, the amounts of residue werecalculated according to the following equation after recovering residuesupon vaporization.

Amount of residue=(weight of residues at vaporization/weight of thecompounds before dissolution)×100 (%)

In Table 3, THF indicates the organic solvent tetrahydrofuran, and MeTHFindicates the organic solvent methyltetrahydrofuran.

TABLE 3 Organo Organo Zr Pb Organo Ti Organic Residue compound compoundcompound solvent rate (%) Ex. 1 Zr(tBuO)₁(thd)₃ Pb(thd)₂ — THF 0.1 Ex. 1Zr(tBuO)₁(thd)₃ Pb(thd)₂ Ti(iPrO)₂(thd)₂ THF 1.2 Ex. 1 Zr(tBuO)₁(thd)₃Pb(thd)₂ Ti(tBuO)₂(thd)₂ THF 0.5 Ex. 1 Zr(tBuO)₁(thd)₃ Pb(thd)₂Ti(tAmylO)₂(thd)₂ MeTHF 0.8 Ex. 2 Zr(tAmylO)₁(thd)₃ Pb(thd)₂ — MeTHF 0.3Ex. 2 Zr(tAmylO)₁(thd)₃ Pb(thd)₂ Ti(tBuiPrO)₂(thd)₂ THF 0.7 Ex. 3Zr(tBuO)₁(tod)₃ Pb(thd)₂ Ti(tAmylO)₂(thd)₂ Octane 1.2 Comp. Ex. 5Zr(iPrO)₁(thd)₃ Pb(thd)₂ — THF 2.0 Comp. Ex. 5 Zr(iPrO)₁(thd)₃ Pb(thd)₂Ti(iPrO)₂(thd)₂ THF 6.3 Comp. Ex. 6 Zr(nBuO)₁(thd)₃ Pb(thd)₂Ti(iPrO)₂(thd)₂ THF 7.1

TABLE 4 Vaporization Vaporization temperature 250° C. conditionVaporization pressure 4,000 Pa Flow amount of raw material 0.2 cc/min N₂flow amount   200 sccm Test period   80 hrs

As is evident from Table 3, the vaporization properties after mixing theorganozirconium compounds described in Examples 1 to 3 with otherorganometallic compounds are extremely excellent as evidenced by theirextremely small amounts of residue produced in the range from 0.1 to1.2% in comparison to those of Comparative Examples 5 and 6 in the rangefrom 2.0 to 7.1%.

As described above, the organozirconium compound of the presentinvention has a lower vaporization temperature and a lower decompositiontemperature in comparison with the prior art Zr(thd)₄, and does notproduce increases amounts of residues upon vaporization when mixed withPb(thd)₂. Furthermore, the compound shows excellent vaporizationproperties when a vaporizer is used. Accordingly, when the compound ofthe present invention is used as an organozirconium compound in filmdeposition to produce a PZT thin film by an MOCVD method, the organicsolutions, as the raw materials, can be supplied to the MOCVD apparatusin a stable manner, since there is no increase of residues formed uponvaporization caused by mixing of the organozirconium compound with anorganolead compound or an organotitanium compound. Furthermore, controlof film composition can be made more accurately, since the vaporizationtemperature and the decomposition temperature are near to those oforganolead compounds and organotitanium compounds.

The disclosures of Japanese priority applications Ser. Nos. 2000-120473and 2001-004626 filed Apr. 21, 2000 and Jan. 12, 2001 are herebyincorporated by reference into lower vaporization temperature and alower decomposition temperature in comparison with the prior artZr(thd)₄, and does not produce increases amounts of residues uponvaporization when mixed with Pb(thd)₂. Furthermore, the compound showsexcellent vaporization properties when a vaporizer is used. Accordingly,when the compound of the present invention is used as an organozirconiumcompound in film deposition to produce a PZT thin film by an MOCVDmethod, the organic solutions, as the raw materials, can be supplied tothe MOCVD apparatus in a stable manner, since there is no increase ofresidues formed upon vaporization caused by mixing of theorganozirconium compound with an organolead compound or anorganotitanium compound. Furthermore, control of film composition can bemade more accurately, since the vaporization temperature and thedecomposition temperature are near to those of organolead compounds andorganotitanium compounds.

The disclosures of Japanese priority applications Ser. Nos. 2000-120473,2001-004626 and 2001-045877 filed Apr. 21, 2000, Jan. 12, 2001 and Feb.22, 2001 are hereby incorporated by reference into the presentapplication.

Obviously, numerous modifications and variations of the presentinvention are possible in light of the above teachings. It is thereforeto be understood that within the scope of the appended claims, theinvention may be practiced otherwise than as specifically describedherein.

What is claimed as new and is intended to be secured by Letters Patentis:
 1. An organozirconium compound which comprises zirconium combinedwith a β-diketone compound and an alkoxy group having a branched alkylgroup, and which has formula (1):

wherein R is a branched alkyl group having 4 or 5 carbons; and L₁, L₂,and L₃, the same or different from each other, are each a β-diketonecompound.
 2. The organozirconium compound according to claim 1, whereinthe alkoxy group (OR) having a branched alkyl group is a tertiary alkoxygroup.
 3. The organozirconium compound according to claim 1, wherein thebranched alkyl group (R) is a tertiary-butyl group or a tertiary-amylgroup.
 4. The organozirconium compound according to claim 2, wherein thebranched alkyl group (R) is a tertiary-butyl group or a tertiary-amylgroup.
 5. The organozirconium compound according to claim 1, wherein theβ-diketone compound (L₁, L₂, or L₃) has formula (2):

wherein R₁ and R₂ are each a group selected from the group consisting ofmethyl, ethyl, normal-propyl, isopropyl, normal-butyl, isobutyl,tertiary-butyl, tertiary-pentyl, neopentyl, trifluoromethyl andpentafluoroethyl.
 6. An organic solution comprising an organozirconiumcompound according to claim 1, wherein the organozirconium compound isdissolved in an organic solvent together with at least one of Pb(thd)₂or Ti(OR′)₂(thd)₂, in which thd is a2,2,6,6-tetramethyl-3,5-heptadionate group; and R′ is a straight-chainor branched alkyl group having 3 to 5 carbons.
 7. An organic solutioncomprising an organozirconium compound according to claim 1, wherein theorganozirconium compound is dissolved in an organic solvent togetherwith at least one of Pb(tod)₂ or Ti(OR′)₂(tod)₂, in which tod is a2,2,6,6-tetramethyl-3,5-octadionate group; and R′ is a straight-chain orbranched alkyl group having 3 to 5 carbons.
 8. The organic solutionaccording to claim 6, wherein R′ is the same as the branched alkyl group(R) in the compound of formula (1).
 9. The organic solution according toclaim 7, wherein R′ is the same as the branched alkyl group (R) in thecompound of formula (1).
 10. The organic solution according to claim 6,wherein the organic solvent is tetrahydrofuran, methyl tetrahydrofuran,butyl acetate or octane.
 11. The organic solution according to claim 7,wherein the organic solvent is tetrahydrofuran, methyl tetrahydrofuran,butyl acetate or octane.
 12. A zirconium-containing thin film preparedby: chemically depositing an organozirconium compound according to claim1 onto a substrate.
 13. A zirconium-containing thin film prepared by:chemically depositing an organozirconium compound according to claim 2onto a substrate.
 14. A zirconium-containing thin film prepared by:forming a film of an organozirconium compound of claim 1 in an organicsolution on a substrate.
 15. A zirconium-containing thin film preparedby: forming a film of an organozirconium compound of claim 2 in anorganic solution on a substrate.